monitor.c

   1 /*
   2  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
   3  * Copyright 2002 Markus Friedl <markus@openbsd.org>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include "includes.h"
  28 RCSID("$OpenBSD: monitor.c,v 1.63 2005/03/10 22:01:05 deraadt Exp $");
  29
  30 #include <openssl/dh.h>
  31
  32 #ifdef SKEY
  33 #include <skey.h>
  34 #endif
  35
  36 #include "ssh.h"
  37 #include "auth.h"
  38 #include "kex.h"
  39 #include "dh.h"
  40 #ifdef TARGET_OS_MAC    /* XXX Broken krb5 headers on Mac */
  41 #undef TARGET_OS_MAC
  42 #include "zlib.h"
  43 #define TARGET_OS_MAC 1
  44 #else
  45 #include "zlib.h"
  46 #endif
  47 #include "packet.h"
  48 #include "auth-options.h"
  49 #include "sshpty.h"
  50 #include "channels.h"
  51 #include "session.h"
  52 #include "sshlogin.h"
  53 #include "canohost.h"
  54 #include "log.h"
  55 #include "servconf.h"
  56 #include "monitor.h"
  57 #include "monitor_mm.h"
  58 #include "monitor_wrap.h"
  59 #include "monitor_fdpass.h"
  60 #include "xmalloc.h"
  61 #include "misc.h"
  62 #include "buffer.h"
  63 #include "bufaux.h"
  64 #include "compat.h"
  65 #include "ssh2.h"
  66
  67 #ifdef GSSAPI
  68 #include "ssh-gss.h"
  69 static Gssctxt *gsscontext = NULL;
  70 #endif
  71
  72 /* Imports */
  73 extern ServerOptions options;
  74 extern u_int utmp_len;
  75 extern Newkeys *current_keys[];
  76 extern z_stream incoming_stream;
  77 extern z_stream outgoing_stream;
  78 extern u_char session_id[];
  79 extern Buffer input, output;
  80 extern Buffer auth_debug;
  81 extern int auth_debug_init;
  82 extern Buffer loginmsg;
  83
  84 /* State exported from the child */
  85
  86 struct {
  87         z_stream incoming;
  88         z_stream outgoing;
  89         u_char *keyin;
  90         u_int keyinlen;
  91         u_char *keyout;
  92         u_int keyoutlen;
  93         u_char *ivin;
  94         u_int ivinlen;
  95         u_char *ivout;
  96         u_int ivoutlen;
  97         u_char *ssh1key;
  98         u_int ssh1keylen;
  99         int ssh1cipher;
 100         int ssh1protoflags;
 101         u_char *input;
 102         u_int ilen;
 103         u_char *output;
 104         u_int olen;
 105 } child_state;
 106
 107 /* Functions on the monitor that answer unprivileged requests */
 108
 109 int mm_answer_moduli(int, Buffer *);
 110 int mm_answer_sign(int, Buffer *);
 111 int mm_answer_pwnamallow(int, Buffer *);
 112 int mm_answer_auth2_read_banner(int, Buffer *);
 113 int mm_answer_authserv(int, Buffer *);
 114 int mm_answer_authpassword(int, Buffer *);
 115 int mm_answer_bsdauthquery(int, Buffer *);
 116 int mm_answer_bsdauthrespond(int, Buffer *);
 117 int mm_answer_skeyquery(int, Buffer *);
 118 int mm_answer_skeyrespond(int, Buffer *);
 119 int mm_answer_keyallowed(int, Buffer *);
 120 int mm_answer_keyverify(int, Buffer *);
 121 int mm_answer_pty(int, Buffer *);
 122 int mm_answer_pty_cleanup(int, Buffer *);
 123 int mm_answer_term(int, Buffer *);
 124 int mm_answer_rsa_keyallowed(int, Buffer *);
 125 int mm_answer_rsa_challenge(int, Buffer *);
 126 int mm_answer_rsa_response(int, Buffer *);
 127 int mm_answer_sesskey(int, Buffer *);
 128 int mm_answer_sessid(int, Buffer *);
 129
 130 #ifdef USE_PAM
 131 int mm_answer_pam_start(int, Buffer *);
 132 int mm_answer_pam_account(int, Buffer *);
 133 int mm_answer_pam_init_ctx(int, Buffer *);
 134 int mm_answer_pam_query(int, Buffer *);
 135 int mm_answer_pam_respond(int, Buffer *);
 136 int mm_answer_pam_free_ctx(int, Buffer *);
 137 #endif
 138
 139 #ifdef GSSAPI
 140 int mm_answer_gss_setup_ctx(int, Buffer *);
 141 int mm_answer_gss_accept_ctx(int, Buffer *);
 142 int mm_answer_gss_userok(int, Buffer *);
 143 int mm_answer_gss_checkmic(int, Buffer *);
 144 #endif
 145
 146 #ifdef SSH_AUDIT_EVENTS
 147 int mm_answer_audit_event(int, Buffer *);
 148 int mm_answer_audit_command(int, Buffer *);
 149 #endif
 150
 151 static Authctxt *authctxt;
 152 static BIGNUM *ssh1_challenge = NULL;   /* used for ssh1 rsa auth */
 153
 154 /* local state for key verify */
 155 static u_char *key_blob = NULL;
 156 static u_int key_bloblen = 0;
 157 static int key_blobtype = MM_NOKEY;
 158 static char *hostbased_cuser = NULL;
 159 static char *hostbased_chost = NULL;
 160 static char *auth_method = "unknown";
 161 static u_int session_id2_len = 0;
 162 static u_char *session_id2 = NULL;
 163 static pid_t monitor_child_pid;
 164
 165 struct mon_table {
 166         enum monitor_reqtype type;
 167         int flags;
 168         int (*f)(int, Buffer *);
 169 };
 170
 171 #define MON_ISAUTH      0x0004  /* Required for Authentication */
 172 #define MON_AUTHDECIDE  0x0008  /* Decides Authentication */
 173 #define MON_ONCE        0x0010  /* Disable after calling */
 174
 175 #define MON_AUTH        (MON_ISAUTH|MON_AUTHDECIDE)
 176
 177 #define MON_PERMIT      0x1000  /* Request is permitted */
 178
 179 struct mon_table mon_dispatch_proto20[] = {
 180     {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli},
 181     {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign},
 182     {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
 183     {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv},
 184     {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner},
 185     {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
 186 #ifdef USE_PAM
 187     {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
 188     {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account},
 189     {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx},
 190     {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query},
 191     {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond},
 192     {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
 193 #endif
 194 #ifdef SSH_AUDIT_EVENTS
 195     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 196 #endif
 197 #ifdef BSD_AUTH
 198     {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
 199     {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH,mm_answer_bsdauthrespond},
 200 #endif
 201 #ifdef SKEY
 202     {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery},
 203     {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond},
 204 #endif
 205     {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed},
 206     {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify},
 207 #ifdef GSSAPI
 208     {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx},
 209     {MONITOR_REQ_GSSSTEP, MON_ISAUTH, mm_answer_gss_accept_ctx},
 210     {MONITOR_REQ_GSSUSEROK, MON_AUTH, mm_answer_gss_userok},
 211     {MONITOR_REQ_GSSCHECKMIC, MON_ISAUTH, mm_answer_gss_checkmic},
 212 #endif
 213     {0, 0, NULL}
 214 };
 215
 216 struct mon_table mon_dispatch_postauth20[] = {
 217     {MONITOR_REQ_MODULI, 0, mm_answer_moduli},
 218     {MONITOR_REQ_SIGN, 0, mm_answer_sign},
 219     {MONITOR_REQ_PTY, 0, mm_answer_pty},
 220     {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup},
 221     {MONITOR_REQ_TERM, 0, mm_answer_term},
 222 #ifdef SSH_AUDIT_EVENTS
 223     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 224     {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command},
 225 #endif
 226     {0, 0, NULL}
 227 };
 228
 229 struct mon_table mon_dispatch_proto15[] = {
 230     {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
 231     {MONITOR_REQ_SESSKEY, MON_ONCE, mm_answer_sesskey},
 232     {MONITOR_REQ_SESSID, MON_ONCE, mm_answer_sessid},
 233     {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
 234     {MONITOR_REQ_RSAKEYALLOWED, MON_ISAUTH, mm_answer_rsa_keyallowed},
 235     {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed},
 236     {MONITOR_REQ_RSACHALLENGE, MON_ONCE, mm_answer_rsa_challenge},
 237     {MONITOR_REQ_RSARESPONSE, MON_ONCE|MON_AUTHDECIDE, mm_answer_rsa_response},
 238 #ifdef BSD_AUTH
 239     {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
 240     {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH,mm_answer_bsdauthrespond},
 241 #endif
 242 #ifdef SKEY
 243     {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery},
 244     {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond},
 245 #endif
 246 #ifdef USE_PAM
 247     {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
 248     {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account},
 249     {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx},
 250     {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query},
 251     {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond},
 252     {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
 253 #endif
 254 #ifdef SSH_AUDIT_EVENTS
 255     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 256 #endif
 257     {0, 0, NULL}
 258 };
 259
 260 struct mon_table mon_dispatch_postauth15[] = {
 261     {MONITOR_REQ_PTY, MON_ONCE, mm_answer_pty},
 262     {MONITOR_REQ_PTYCLEANUP, MON_ONCE, mm_answer_pty_cleanup},
 263     {MONITOR_REQ_TERM, 0, mm_answer_term},
 264 #ifdef SSH_AUDIT_EVENTS
 265     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 266     {MONITOR_REQ_AUDIT_COMMAND, MON_ONCE, mm_answer_audit_command},
 267 #endif
 268     {0, 0, NULL}
 269 };
 270
 271 struct mon_table *mon_dispatch;
 272
 273 /* Specifies if a certain message is allowed at the moment */
 274
 275 static void
 276 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit)
 277 {
 278         while (ent->f != NULL) {
 279                 if (ent->type == type) {
 280                         ent->flags &= ~MON_PERMIT;
 281                         ent->flags |= permit ? MON_PERMIT : 0;
 282                         return;
 283                 }
 284                 ent++;
 285         }
 286 }
 287
 288 static void
 289 monitor_permit_authentications(int permit)
 290 {
 291         struct mon_table *ent = mon_dispatch;
 292
 293         while (ent->f != NULL) {
 294                 if (ent->flags & MON_AUTH) {
 295                         ent->flags &= ~MON_PERMIT;
 296                         ent->flags |= permit ? MON_PERMIT : 0;
 297                 }
 298                 ent++;
 299         }
 300 }
 301
 302 void
 303 monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor)
 304 {
 305         struct mon_table *ent;
 306         int authenticated = 0;
 307
 308         debug3("preauth child monitor started");
 309
 310         authctxt = _authctxt;
 311         memset(authctxt, 0, sizeof(*authctxt));
 312
 313         authctxt->loginmsg = &loginmsg;
 314
 315         if (compat20) {
 316                 mon_dispatch = mon_dispatch_proto20;
 317
 318                 /* Permit requests for moduli and signatures */
 319                 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
 320                 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
 321         } else {
 322                 mon_dispatch = mon_dispatch_proto15;
 323
 324                 monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 1);
 325         }
 326
 327         /* The first few requests do not require asynchronous access */
 328         while (!authenticated) {
 329                 authenticated = monitor_read(pmonitor, mon_dispatch, &ent);
 330                 if (authenticated) {
 331                         if (!(ent->flags & MON_AUTHDECIDE))
 332                                 fatal("%s: unexpected authentication from %d",
 333                                     __func__, ent->type);
 334                         if (authctxt->pw->pw_uid == 0 &&
 335                             !auth_root_allowed(auth_method))
 336                                 authenticated = 0;
 337 #ifdef USE_PAM
 338                         /* PAM needs to perform account checks after auth */
 339                         if (options.use_pam && authenticated) {
 340                                 Buffer m;
 341
 342                                 buffer_init(&m);
 343                                 mm_request_receive_expect(pmonitor->m_sendfd,
 344                                     MONITOR_REQ_PAM_ACCOUNT, &m);
 345                                 authenticated = mm_answer_pam_account(pmonitor->m_sendfd, &m);
 346                                 buffer_free(&m);
 347                         }
 348 #endif
 349                 }
 350
 351                 if (ent->flags & MON_AUTHDECIDE) {
 352                         auth_log(authctxt, authenticated, auth_method,
 353                             compat20 ? " ssh2" : "");
 354                         if (!authenticated)
 355                                 authctxt->failures++;
 356                 }
 357         }
 358
 359         if (!authctxt->valid)
 360                 fatal("%s: authenticated invalid user", __func__);
 361
 362         debug("%s: %s has been authenticated by privileged process",
 363             __func__, authctxt->user);
 364
 365         mm_get_keystate(pmonitor);
 366 }
 367
 368 static void
 369 monitor_set_child_handler(pid_t pid)
 370 {
 371         monitor_child_pid = pid;
 372 }
 373
 374 static void
 375 monitor_child_handler(int sig)
 376 {
 377         kill(monitor_child_pid, sig);
 378 }
 379
 380 void
 381 monitor_child_postauth(struct monitor *pmonitor)
 382 {
 383         monitor_set_child_handler(pmonitor->m_pid);
 384         signal(SIGHUP, &monitor_child_handler);
 385         signal(SIGTERM, &monitor_child_handler);
 386
 387         if (compat20) {
 388                 mon_dispatch = mon_dispatch_postauth20;
 389
 390                 /* Permit requests for moduli and signatures */
 391                 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
 392                 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
 393                 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
 394         } else {
 395                 mon_dispatch = mon_dispatch_postauth15;
 396                 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
 397         }
 398         if (!no_pty_flag) {
 399                 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1);
 400                 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1);
 401         }
 402
 403         for (;;)
 404                 monitor_read(pmonitor, mon_dispatch, NULL);
 405 }
 406
 407 void
 408 monitor_sync(struct monitor *pmonitor)
 409 {
 410         if (options.compression) {
 411                 /* The member allocation is not visible, so sync it */
 412                 mm_share_sync(&pmonitor->m_zlib, &pmonitor->m_zback);
 413         }
 414 }
 415
 416 int
 417 monitor_read(struct monitor *pmonitor, struct mon_table *ent,
 418     struct mon_table **pent)
 419 {
 420         Buffer m;
 421         int ret;
 422         u_char type;
 423
 424         buffer_init(&m);
 425
 426         mm_request_receive(pmonitor->m_sendfd, &m);
 427         type = buffer_get_char(&m);
 428
 429         debug3("%s: checking request %d", __func__, type);
 430
 431         while (ent->f != NULL) {
 432                 if (ent->type == type)
 433                         break;
 434                 ent++;
 435         }
 436
 437         if (ent->f != NULL) {
 438                 if (!(ent->flags & MON_PERMIT))
 439                         fatal("%s: unpermitted request %d", __func__,
 440                             type);
 441                 ret = (*ent->f)(pmonitor->m_sendfd, &m);
 442                 buffer_free(&m);
 443
 444                 /* The child may use this request only once, disable it */
 445                 if (ent->flags & MON_ONCE) {
 446                         debug2("%s: %d used once, disabling now", __func__,
 447                             type);
 448                         ent->flags &= ~MON_PERMIT;
 449                 }
 450
 451                 if (pent != NULL)
 452                         *pent = ent;
 453
 454                 return ret;
 455         }
 456
 457         fatal("%s: unsupported request: %d", __func__, type);
 458
 459         /* NOTREACHED */
 460         return (-1);
 461 }
 462
 463 /* allowed key state */
 464 static int
 465 monitor_allowed_key(u_char *blob, u_int bloblen)
 466 {
 467         /* make sure key is allowed */
 468         if (key_blob == NULL || key_bloblen != bloblen ||
 469             memcmp(key_blob, blob, key_bloblen))
 470                 return (0);
 471         return (1);
 472 }
 473
 474 static void
 475 monitor_reset_key_state(void)
 476 {
 477         /* reset state */
 478         if (key_blob != NULL)
 479                 xfree(key_blob);
 480         if (hostbased_cuser != NULL)
 481                 xfree(hostbased_cuser);
 482         if (hostbased_chost != NULL)
 483                 xfree(hostbased_chost);
 484         key_blob = NULL;
 485         key_bloblen = 0;
 486         key_blobtype = MM_NOKEY;
 487         hostbased_cuser = NULL;
 488         hostbased_chost = NULL;
 489 }
 490
 491 int
 492 mm_answer_moduli(int sock, Buffer *m)
 493 {
 494         DH *dh;
 495         int min, want, max;
 496
 497         min = buffer_get_int(m);
 498         want = buffer_get_int(m);
 499         max = buffer_get_int(m);
 500
 501         debug3("%s: got parameters: %d %d %d",
 502             __func__, min, want, max);
 503         /* We need to check here, too, in case the child got corrupted */
 504         if (max < min || want < min || max < want)
 505                 fatal("%s: bad parameters: %d %d %d",
 506                     __func__, min, want, max);
 507
 508         buffer_clear(m);
 509
 510         dh = choose_dh(min, want, max);
 511         if (dh == NULL) {
 512                 buffer_put_char(m, 0);
 513                 return (0);
 514         } else {
 515                 /* Send first bignum */
 516                 buffer_put_char(m, 1);
 517                 buffer_put_bignum2(m, dh->p);
 518                 buffer_put_bignum2(m, dh->g);
 519
 520                 DH_free(dh);
 521         }
 522         mm_request_send(sock, MONITOR_ANS_MODULI, m);
 523         return (0);
 524 }
 525
 526 int
 527 mm_answer_sign(int sock, Buffer *m)
 528 {
 529         Key *key;
 530         u_char *p;
 531         u_char *signature;
 532         u_int siglen, datlen;
 533         int keyid;
 534
 535         debug3("%s", __func__);
 536
 537         keyid = buffer_get_int(m);
 538         p = buffer_get_string(m, &datlen);
 539
 540         if (datlen != 20)
 541                 fatal("%s: data length incorrect: %u", __func__, datlen);
 542
 543         /* save session id, it will be passed on the first call */
 544         if (session_id2_len == 0) {
 545                 session_id2_len = datlen;
 546                 session_id2 = xmalloc(session_id2_len);
 547                 memcpy(session_id2, p, session_id2_len);
 548         }
 549
 550         if ((key = get_hostkey_by_index(keyid)) == NULL)
 551                 fatal("%s: no hostkey from index %d", __func__, keyid);
 552         if (key_sign(key, &signature, &siglen, p, datlen) < 0)
 553                 fatal("%s: key_sign failed", __func__);
 554
 555         debug3("%s: signature %p(%u)", __func__, signature, siglen);
 556
 557         buffer_clear(m);
 558         buffer_put_string(m, signature, siglen);
 559
 560         xfree(p);
 561         xfree(signature);
 562
 563         mm_request_send(sock, MONITOR_ANS_SIGN, m);
 564
 565         /* Turn on permissions for getpwnam */
 566         monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
 567
 568         return (0);
 569 }
 570
 571 /* Retrieves the password entry and also checks if the user is permitted */
 572
 573 int
 574 mm_answer_pwnamallow(int sock, Buffer *m)
 575 {
 576         char *username;
 577         struct passwd *pwent;
 578         int allowed = 0;
 579
 580         debug3("%s", __func__);
 581
 582         if (authctxt->attempt++ != 0)
 583                 fatal("%s: multiple attempts for getpwnam", __func__);
 584
 585         username = buffer_get_string(m, NULL);
 586
 587         pwent = getpwnamallow(username);
 588
 589         authctxt->user = xstrdup(username);
 590         setproctitle("%s [priv]", pwent ? username : "unknown");
 591         xfree(username);
 592
 593         buffer_clear(m);
 594
 595         if (pwent == NULL) {
 596                 buffer_put_char(m, 0);
 597                 authctxt->pw = fakepw();
 598                 goto out;
 599         }
 600
 601         allowed = 1;
 602         authctxt->pw = pwent;
 603         authctxt->valid = 1;
 604
 605         buffer_put_char(m, 1);
 606         buffer_put_string(m, pwent, sizeof(struct passwd));
 607         buffer_put_cstring(m, pwent->pw_name);
 608         buffer_put_cstring(m, "*");
 609         buffer_put_cstring(m, pwent->pw_gecos);
 610 #ifdef HAVE_PW_CLASS_IN_PASSWD
 611         buffer_put_cstring(m, pwent->pw_class);
 612 #endif
 613         buffer_put_cstring(m, pwent->pw_dir);
 614         buffer_put_cstring(m, pwent->pw_shell);
 615
 616  out:
 617         debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed);
 618         mm_request_send(sock, MONITOR_ANS_PWNAM, m);
 619
 620         /* For SSHv1 allow authentication now */
 621         if (!compat20)
 622                 monitor_permit_authentications(1);
 623         else {
 624                 /* Allow service/style information on the auth context */
 625                 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1);
 626                 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1);
 627         }
 628
 629 #ifdef USE_PAM
 630         if (options.use_pam)
 631                 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1);
 632 #endif
 633 #ifdef SSH_AUDIT_EVENTS
 634         monitor_permit(mon_dispatch, MONITOR_REQ_AUDIT_COMMAND, 1);
 635 #endif
 636
 637         return (0);
 638 }
 639
 640 int mm_answer_auth2_read_banner(int sock, Buffer *m)
 641 {
 642         char *banner;
 643
 644         buffer_clear(m);
 645         banner = auth2_read_banner();
 646         buffer_put_cstring(m, banner != NULL ? banner : "");
 647         mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m);
 648
 649         if (banner != NULL)
 650                 xfree(banner);
 651
 652         return (0);
 653 }
 654
 655 int
 656 mm_answer_authserv(int sock, Buffer *m)
 657 {
 658         monitor_permit_authentications(1);
 659
 660         authctxt->service = buffer_get_string(m, NULL);
 661         authctxt->style = buffer_get_string(m, NULL);
 662         debug3("%s: service=%s, style=%s",
 663             __func__, authctxt->service, authctxt->style);
 664
 665         if (strlen(authctxt->style) == 0) {
 666                 xfree(authctxt->style);
 667                 authctxt->style = NULL;
 668         }
 669
 670         return (0);
 671 }
 672
 673 int
 674 mm_answer_authpassword(int sock, Buffer *m)
 675 {
 676         static int call_count;
 677         char *passwd;
 678         int authenticated;
 679         u_int plen;
 680
 681         passwd = buffer_get_string(m, &plen);
 682         /* Only authenticate if the context is valid */
 683         authenticated = options.password_authentication &&
 684             auth_password(authctxt, passwd);
 685         memset(passwd, 0, strlen(passwd));
 686         xfree(passwd);
 687
 688         buffer_clear(m);
 689         buffer_put_int(m, authenticated);
 690
 691         debug3("%s: sending result %d", __func__, authenticated);
 692         mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m);
 693
 694         call_count++;
 695         if (plen == 0 && call_count == 1)
 696                 auth_method = "none";
 697         else
 698                 auth_method = "password";
 699
 700         /* Causes monitor loop to terminate if authenticated */
 701         return (authenticated);
 702 }
 703
 704 #ifdef BSD_AUTH
 705 int
 706 mm_answer_bsdauthquery(int sock, Buffer *m)
 707 {
 708         char *name, *infotxt;
 709         u_int numprompts;
 710         u_int *echo_on;
 711         char **prompts;
 712         u_int success;
 713
 714         success = bsdauth_query(authctxt, &name, &infotxt, &numprompts,
 715             &prompts, &echo_on) < 0 ? 0 : 1;
 716
 717         buffer_clear(m);
 718         buffer_put_int(m, success);
 719         if (success)
 720                 buffer_put_cstring(m, prompts[0]);
 721
 722         debug3("%s: sending challenge success: %u", __func__, success);
 723         mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m);
 724
 725         if (success) {
 726                 xfree(name);
 727                 xfree(infotxt);
 728                 xfree(prompts);
 729                 xfree(echo_on);
 730         }
 731
 732         return (0);
 733 }
 734
 735 int
 736 mm_answer_bsdauthrespond(int sock, Buffer *m)
 737 {
 738         char *response;
 739         int authok;
 740
 741         if (authctxt->as == 0)
 742                 fatal("%s: no bsd auth session", __func__);
 743
 744         response = buffer_get_string(m, NULL);
 745         authok = options.challenge_response_authentication &&
 746             auth_userresponse(authctxt->as, response, 0);
 747         authctxt->as = NULL;
 748         debug3("%s: <%s> = <%d>", __func__, response, authok);
 749         xfree(response);
 750
 751         buffer_clear(m);
 752         buffer_put_int(m, authok);
 753
 754         debug3("%s: sending authenticated: %d", __func__, authok);
 755         mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m);
 756
 757         auth_method = "bsdauth";
 758
 759         return (authok != 0);
 760 }
 761 #endif
 762
 763 #ifdef SKEY
 764 int
 765 mm_answer_skeyquery(int sock, Buffer *m)
 766 {
 767         struct skey skey;
 768         char challenge[1024];
 769         u_int success;
 770
 771         success = _compat_skeychallenge(&skey, authctxt->user, challenge,
 772             sizeof(challenge)) < 0 ? 0 : 1;
 773
 774         buffer_clear(m);
 775         buffer_put_int(m, success);
 776         if (success)
 777                 buffer_put_cstring(m, challenge);
 778
 779         debug3("%s: sending challenge success: %u", __func__, success);
 780         mm_request_send(sock, MONITOR_ANS_SKEYQUERY, m);
 781
 782         return (0);
 783 }
 784
 785 int
 786 mm_answer_skeyrespond(int sock, Buffer *m)
 787 {
 788         char *response;
 789         int authok;
 790
 791         response = buffer_get_string(m, NULL);
 792
 793         authok = (options.challenge_response_authentication &&
 794             authctxt->valid &&
 795             skey_haskey(authctxt->pw->pw_name) == 0 &&
 796             skey_passcheck(authctxt->pw->pw_name, response) != -1);
 797
 798         xfree(response);
 799
 800         buffer_clear(m);
 801         buffer_put_int(m, authok);
 802
 803         debug3("%s: sending authenticated: %d", __func__, authok);
 804         mm_request_send(sock, MONITOR_ANS_SKEYRESPOND, m);
 805
 806         auth_method = "skey";
 807
 808         return (authok != 0);
 809 }
 810 #endif
 811
 812 #ifdef USE_PAM
 813 int
 814 mm_answer_pam_start(int sock, Buffer *m)
 815 {
 816         if (!options.use_pam)
 817                 fatal("UsePAM not set, but ended up in %s anyway", __func__);
 818
 819         start_pam(authctxt);
 820
 821         monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1);
 822
 823         return (0);
 824 }
 825
 826 int
 827 mm_answer_pam_account(int sock, Buffer *m)
 828 {
 829         u_int ret;
 830
 831         if (!options.use_pam)
 832                 fatal("UsePAM not set, but ended up in %s anyway", __func__);
 833
 834         ret = do_pam_account();
 835
 836         buffer_put_int(m, ret);
 837         buffer_append(&loginmsg, "\0", 1);
 838         buffer_put_cstring(m, buffer_ptr(&loginmsg));
 839         buffer_clear(&loginmsg);
 840
 841         mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m);
 842
 843         return (ret);
 844 }
 845
 846 static void *sshpam_ctxt, *sshpam_authok;
 847 extern KbdintDevice sshpam_device;
 848
 849 int
 850 mm_answer_pam_init_ctx(int sock, Buffer *m)
 851 {
 852
 853         debug3("%s", __func__);
 854         authctxt->user = buffer_get_string(m, NULL);
 855         sshpam_ctxt = (sshpam_device.init_ctx)(authctxt);
 856         sshpam_authok = NULL;
 857         buffer_clear(m);
 858         if (sshpam_ctxt != NULL) {
 859                 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1);
 860                 buffer_put_int(m, 1);
 861         } else {
 862                 buffer_put_int(m, 0);
 863         }
 864         mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m);
 865         return (0);
 866 }
 867
 868 int
 869 mm_answer_pam_query(int sock, Buffer *m)
 870 {
 871         char *name, *info, **prompts;
 872         u_int i, num, *echo_on;
 873         int ret;
 874
 875         debug3("%s", __func__);
 876         sshpam_authok = NULL;
 877         ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, &num, &prompts, &echo_on);
 878         if (ret == 0 && num == 0)
 879                 sshpam_authok = sshpam_ctxt;
 880         if (num > 1 || name == NULL || info == NULL)
 881                 ret = -1;
 882         buffer_clear(m);
 883         buffer_put_int(m, ret);
 884         buffer_put_cstring(m, name);
 885         xfree(name);
 886         buffer_put_cstring(m, info);
 887         xfree(info);
 888         buffer_put_int(m, num);
 889         for (i = 0; i < num; ++i) {
 890                 buffer_put_cstring(m, prompts[i]);
 891                 xfree(prompts[i]);
 892                 buffer_put_int(m, echo_on[i]);
 893         }
 894         if (prompts != NULL)
 895                 xfree(prompts);
 896         if (echo_on != NULL)
 897                 xfree(echo_on);
 898         mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m);
 899         return (0);
 900 }
 901
 902 int
 903 mm_answer_pam_respond(int sock, Buffer *m)
 904 {
 905         char **resp;
 906         u_int i, num;
 907         int ret;
 908
 909         debug3("%s", __func__);
 910         sshpam_authok = NULL;
 911         num = buffer_get_int(m);
 912         if (num > 0) {
 913                 resp = xmalloc(num * sizeof(char *));
 914                 for (i = 0; i < num; ++i)
 915                         resp[i] = buffer_get_string(m, NULL);
 916                 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp);
 917                 for (i = 0; i < num; ++i)
 918                         xfree(resp[i]);
 919                 xfree(resp);
 920         } else {
 921                 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL);
 922         }
 923         buffer_clear(m);
 924         buffer_put_int(m, ret);
 925         mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m);
 926         auth_method = "keyboard-interactive/pam";
 927         if (ret == 0)
 928                 sshpam_authok = sshpam_ctxt;
 929         return (0);
 930 }
 931
 932 int
 933 mm_answer_pam_free_ctx(int sock, Buffer *m)
 934 {
 935
 936         debug3("%s", __func__);
 937         (sshpam_device.free_ctx)(sshpam_ctxt);
 938         buffer_clear(m);
 939         mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m);
 940         return (sshpam_authok == sshpam_ctxt);
 941 }
 942 #endif
 943
 944 static void
 945 mm_append_debug(Buffer *m)
 946 {
 947         if (auth_debug_init && buffer_len(&auth_debug)) {
 948                 debug3("%s: Appending debug messages for child", __func__);
 949                 buffer_append(m, buffer_ptr(&auth_debug),
 950                     buffer_len(&auth_debug));
 951                 buffer_clear(&auth_debug);
 952         }
 953 }
 954
 955 int
 956 mm_answer_keyallowed(int sock, Buffer *m)
 957 {
 958         Key *key;
 959         char *cuser, *chost;
 960         u_char *blob;
 961         u_int bloblen;
 962         enum mm_keytype type = 0;
 963         int allowed = 0;
 964
 965         debug3("%s entering", __func__);
 966
 967         type = buffer_get_int(m);
 968         cuser = buffer_get_string(m, NULL);
 969         chost = buffer_get_string(m, NULL);
 970         blob = buffer_get_string(m, &bloblen);
 971
 972         key = key_from_blob(blob, bloblen);
 973
 974         if ((compat20 && type == MM_RSAHOSTKEY) ||
 975             (!compat20 && type != MM_RSAHOSTKEY))
 976                 fatal("%s: key type and protocol mismatch", __func__);
 977
 978         debug3("%s: key_from_blob: %p", __func__, key);
 979
 980         if (key != NULL && authctxt->valid) {
 981                 switch (type) {
 982                 case MM_USERKEY:
 983                         allowed = options.pubkey_authentication &&
 984                             user_key_allowed(authctxt->pw, key);
 985                         break;
 986                 case MM_HOSTKEY:
 987                         allowed = options.hostbased_authentication &&
 988                             hostbased_key_allowed(authctxt->pw,
 989                             cuser, chost, key);
 990                         break;
 991                 case MM_RSAHOSTKEY:
 992                         key->type = KEY_RSA1; /* XXX */
 993                         allowed = options.rhosts_rsa_authentication &&
 994                             auth_rhosts_rsa_key_allowed(authctxt->pw,
 995                             cuser, chost, key);
 996                         break;
 997                 default:
 998                         fatal("%s: unknown key type %d", __func__, type);
 999                         break;
1000                 }
1001         }
1002         if (key != NULL)
1003                 key_free(key);
1004
1005         /* clear temporarily storage (used by verify) */
1006         monitor_reset_key_state();
1007
1008         if (allowed) {
1009                 /* Save temporarily for comparison in verify */
1010                 key_blob = blob;
1011                 key_bloblen = bloblen;
1012                 key_blobtype = type;
1013                 hostbased_cuser = cuser;
1014                 hostbased_chost = chost;
1015         }
1016
1017         debug3("%s: key %p is %s",
1018             __func__, key, allowed ? "allowed" : "disallowed");
1019
1020         buffer_clear(m);
1021         buffer_put_int(m, allowed);
1022         buffer_put_int(m, forced_command != NULL);
1023
1024         mm_append_debug(m);
1025
1026         mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m);
1027
1028         if (type == MM_RSAHOSTKEY)
1029                 monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed);
1030
1031         return (0);
1032 }
1033
1034 static int
1035 monitor_valid_userblob(u_char *data, u_int datalen)
1036 {
1037         Buffer b;
1038         char *p;
1039         u_int len;
1040         int fail = 0;
1041
1042         buffer_init(&b);
1043         buffer_append(&b, data, datalen);
1044
1045         if (datafellows & SSH_OLD_SESSIONID) {
1046                 p = buffer_ptr(&b);
1047                 len = buffer_len(&b);
1048                 if ((session_id2 == NULL) ||
1049                     (len < session_id2_len) ||
1050                     (memcmp(p, session_id2, session_id2_len) != 0))
1051                         fail++;
1052                 buffer_consume(&b, session_id2_len);
1053         } else {
1054                 p = buffer_get_string(&b, &len);
1055                 if ((session_id2 == NULL) ||
1056                     (len != session_id2_len) ||
1057                     (memcmp(p, session_id2, session_id2_len) != 0))
1058                         fail++;
1059                 xfree(p);
1060         }
1061         if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
1062                 fail++;
1063         p = buffer_get_string(&b, NULL);
1064         if (strcmp(authctxt->user, p) != 0) {
1065                 logit("wrong user name passed to monitor: expected %s != %.100s",
1066                     authctxt->user, p);
1067                 fail++;
1068         }
1069         xfree(p);
1070         buffer_skip_string(&b);
1071         if (datafellows & SSH_BUG_PKAUTH) {
1072                 if (!buffer_get_char(&b))
1073                         fail++;
1074         } else {
1075                 p = buffer_get_string(&b, NULL);
1076                 if (strcmp("publickey", p) != 0)
1077                         fail++;
1078                 xfree(p);
1079                 if (!buffer_get_char(&b))
1080                         fail++;
1081                 buffer_skip_string(&b);
1082         }
1083         buffer_skip_string(&b);
1084         if (buffer_len(&b) != 0)
1085                 fail++;
1086         buffer_free(&b);
1087         return (fail == 0);
1088 }
1089
1090 static int
1091 monitor_valid_hostbasedblob(u_char *data, u_int datalen, char *cuser,
1092     char *chost)
1093 {
1094         Buffer b;
1095         char *p;
1096         u_int len;
1097         int fail = 0;
1098
1099         buffer_init(&b);
1100         buffer_append(&b, data, datalen);
1101
1102         p = buffer_get_string(&b, &len);
1103         if ((session_id2 == NULL) ||
1104             (len != session_id2_len) ||
1105             (memcmp(p, session_id2, session_id2_len) != 0))
1106                 fail++;
1107         xfree(p);
1108
1109         if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
1110                 fail++;
1111         p = buffer_get_string(&b, NULL);
1112         if (strcmp(authctxt->user, p) != 0) {
1113                 logit("wrong user name passed to monitor: expected %s != %.100s",
1114                     authctxt->user, p);
1115                 fail++;
1116         }
1117         xfree(p);
1118         buffer_skip_string(&b); /* service */
1119         p = buffer_get_string(&b, NULL);
1120         if (strcmp(p, "hostbased") != 0)
1121                 fail++;
1122         xfree(p);
1123         buffer_skip_string(&b); /* pkalg */
1124         buffer_skip_string(&b); /* pkblob */
1125
1126         /* verify client host, strip trailing dot if necessary */
1127         p = buffer_get_string(&b, NULL);
1128         if (((len = strlen(p)) > 0) && p[len - 1] == '.')
1129                 p[len - 1] = '\0';
1130         if (strcmp(p, chost) != 0)
1131                 fail++;
1132         xfree(p);
1133
1134         /* verify client user */
1135         p = buffer_get_string(&b, NULL);
1136         if (strcmp(p, cuser) != 0)
1137                 fail++;
1138         xfree(p);
1139
1140         if (buffer_len(&b) != 0)
1141                 fail++;
1142         buffer_free(&b);
1143         return (fail == 0);
1144 }
1145
1146 int
1147 mm_answer_keyverify(int sock, Buffer *m)
1148 {
1149         Key *key;
1150         u_char *signature, *data, *blob;
1151         u_int signaturelen, datalen, bloblen;
1152         int verified = 0;
1153         int valid_data = 0;
1154
1155         blob = buffer_get_string(m, &bloblen);
1156         signature = buffer_get_string(m, &signaturelen);
1157         data = buffer_get_string(m, &datalen);
1158
1159         if (hostbased_cuser == NULL || hostbased_chost == NULL ||
1160           !monitor_allowed_key(blob, bloblen))
1161                 fatal("%s: bad key, not previously allowed", __func__);
1162
1163         key = key_from_blob(blob, bloblen);
1164         if (key == NULL)
1165                 fatal("%s: bad public key blob", __func__);
1166
1167         switch (key_blobtype) {
1168         case MM_USERKEY:
1169                 valid_data = monitor_valid_userblob(data, datalen);
1170                 break;
1171         case MM_HOSTKEY:
1172                 valid_data = monitor_valid_hostbasedblob(data, datalen,
1173                     hostbased_cuser, hostbased_chost);
1174                 break;
1175         default:
1176                 valid_data = 0;
1177                 break;
1178         }
1179         if (!valid_data)
1180                 fatal("%s: bad signature data blob", __func__);
1181
1182         verified = key_verify(key, signature, signaturelen, data, datalen);
1183         debug3("%s: key %p signature %s",
1184             __func__, key, verified ? "verified" : "unverified");
1185
1186         key_free(key);
1187         xfree(blob);
1188         xfree(signature);
1189         xfree(data);
1190
1191         auth_method = key_blobtype == MM_USERKEY ? "publickey" : "hostbased";
1192
1193         monitor_reset_key_state();
1194
1195         buffer_clear(m);
1196         buffer_put_int(m, verified);
1197         mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m);
1198
1199         return (verified);
1200 }
1201
1202 static void
1203 mm_record_login(Session *s, struct passwd *pw)
1204 {
1205         socklen_t fromlen;
1206         struct sockaddr_storage from;
1207
1208         /*
1209          * Get IP address of client. If the connection is not a socket, let
1210          * the address be 0.0.0.0.
1211          */
1212         memset(&from, 0, sizeof(from));
1213         fromlen = sizeof(from);
1214         if (packet_connection_is_on_socket()) {
1215                 if (getpeername(packet_get_connection_in(),
1216                         (struct sockaddr *) & from, &fromlen) < 0) {
1217                         debug("getpeername: %.100s", strerror(errno));
1218                         cleanup_exit(255);
1219                 }
1220         }
1221         /* Record that there was a login on that tty from the remote host. */
1222         record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid,
1223             get_remote_name_or_ip(utmp_len, options.use_dns),
1224             (struct sockaddr *)&from, fromlen);
1225 }
1226
1227 static void
1228 mm_session_close(Session *s)
1229 {
1230         debug3("%s: session %d pid %ld", __func__, s->self, (long)s->pid);
1231         if (s->ttyfd != -1) {
1232                 debug3("%s: tty %s ptyfd %d",  __func__, s->tty, s->ptyfd);
1233                 session_pty_cleanup2(s);
1234         }
1235         s->used = 0;
1236 }
1237
1238 int
1239 mm_answer_pty(int sock, Buffer *m)
1240 {
1241         extern struct monitor *pmonitor;
1242         Session *s;
1243         int res, fd0;
1244
1245         debug3("%s entering", __func__);
1246
1247         buffer_clear(m);
1248         s = session_new();
1249         if (s == NULL)
1250                 goto error;
1251         s->authctxt = authctxt;
1252         s->pw = authctxt->pw;
1253         s->pid = pmonitor->m_pid;
1254         res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty));
1255         if (res == 0)
1256                 goto error;
1257         pty_setowner(authctxt->pw, s->tty);
1258
1259         buffer_put_int(m, 1);
1260         buffer_put_cstring(m, s->tty);
1261
1262         /* We need to trick ttyslot */
1263         if (dup2(s->ttyfd, 0) == -1)
1264                 fatal("%s: dup2", __func__);
1265
1266         mm_record_login(s, authctxt->pw);
1267
1268         /* Now we can close the file descriptor again */
1269         close(0);
1270
1271         /* send messages generated by record_login */
1272         buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg));
1273         buffer_clear(&loginmsg);
1274
1275         mm_request_send(sock, MONITOR_ANS_PTY, m);
1276
1277         mm_send_fd(sock, s->ptyfd);
1278         mm_send_fd(sock, s->ttyfd);
1279
1280         /* make sure nothing uses fd 0 */
1281         if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) < 0)
1282                 fatal("%s: open(/dev/null): %s", __func__, strerror(errno));
1283         if (fd0 != 0)
1284                 error("%s: fd0 %d != 0", __func__, fd0);
1285
1286         /* slave is not needed */
1287         close(s->ttyfd);
1288         s->ttyfd = s->ptyfd;
1289         /* no need to dup() because nobody closes ptyfd */
1290         s->ptymaster = s->ptyfd;
1291
1292         debug3("%s: tty %s ptyfd %d",  __func__, s->tty, s->ttyfd);
1293
1294         return (0);
1295
1296  error:
1297         if (s != NULL)
1298                 mm_session_close(s);
1299         buffer_put_int(m, 0);
1300         mm_request_send(sock, MONITOR_ANS_PTY, m);
1301         return (0);
1302 }
1303
1304 int
1305 mm_answer_pty_cleanup(int sock, Buffer *m)
1306 {
1307         Session *s;
1308         char *tty;
1309
1310         debug3("%s entering", __func__);
1311
1312         tty = buffer_get_string(m, NULL);
1313         if ((s = session_by_tty(tty)) != NULL)
1314                 mm_session_close(s);
1315         buffer_clear(m);
1316         xfree(tty);
1317         return (0);
1318 }
1319
1320 int
1321 mm_answer_sesskey(int sock, Buffer *m)
1322 {
1323         BIGNUM *p;
1324         int rsafail;
1325
1326         /* Turn off permissions */
1327         monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 0);
1328
1329         if ((p = BN_new()) == NULL)
1330                 fatal("%s: BN_new", __func__);
1331
1332         buffer_get_bignum2(m, p);
1333
1334         rsafail = ssh1_session_key(p);
1335
1336         buffer_clear(m);
1337         buffer_put_int(m, rsafail);
1338         buffer_put_bignum2(m, p);
1339
1340         BN_clear_free(p);
1341
1342         mm_request_send(sock, MONITOR_ANS_SESSKEY, m);
1343
1344         /* Turn on permissions for sessid passing */
1345         monitor_permit(mon_dispatch, MONITOR_REQ_SESSID, 1);
1346
1347         return (0);
1348 }
1349
1350 int
1351 mm_answer_sessid(int sock, Buffer *m)
1352 {
1353         int i;
1354
1355         debug3("%s entering", __func__);
1356
1357         if (buffer_len(m) != 16)
1358                 fatal("%s: bad ssh1 session id", __func__);
1359         for (i = 0; i < 16; i++)
1360                 session_id[i] = buffer_get_char(m);
1361
1362         /* Turn on permissions for getpwnam */
1363         monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
1364
1365         return (0);
1366 }
1367
1368 int
1369 mm_answer_rsa_keyallowed(int sock, Buffer *m)
1370 {
1371         BIGNUM *client_n;
1372         Key *key = NULL;
1373         u_char *blob = NULL;
1374         u_int blen = 0;
1375         int allowed = 0;
1376
1377         debug3("%s entering", __func__);
1378
1379         if (options.rsa_authentication && authctxt->valid) {
1380                 if ((client_n = BN_new()) == NULL)
1381                         fatal("%s: BN_new", __func__);
1382                 buffer_get_bignum2(m, client_n);
1383                 allowed = auth_rsa_key_allowed(authctxt->pw, client_n, &key);
1384                 BN_clear_free(client_n);
1385         }
1386         buffer_clear(m);
1387         buffer_put_int(m, allowed);
1388         buffer_put_int(m, forced_command != NULL);
1389
1390         /* clear temporarily storage (used by generate challenge) */
1391         monitor_reset_key_state();
1392
1393         if (allowed && key != NULL) {
1394                 key->type = KEY_RSA;    /* cheat for key_to_blob */
1395                 if (key_to_blob(key, &blob, &blen) == 0)
1396                         fatal("%s: key_to_blob failed", __func__);
1397                 buffer_put_string(m, blob, blen);
1398
1399                 /* Save temporarily for comparison in verify */
1400                 key_blob = blob;
1401                 key_bloblen = blen;
1402                 key_blobtype = MM_RSAUSERKEY;
1403         }
1404         if (key != NULL)
1405                 key_free(key);
1406
1407         mm_append_debug(m);
1408
1409         mm_request_send(sock, MONITOR_ANS_RSAKEYALLOWED, m);
1410
1411         monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed);
1412         monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 0);
1413         return (0);
1414 }
1415
1416 int
1417 mm_answer_rsa_challenge(int sock, Buffer *m)
1418 {
1419         Key *key = NULL;
1420         u_char *blob;
1421         u_int blen;
1422
1423         debug3("%s entering", __func__);
1424
1425         if (!authctxt->valid)
1426                 fatal("%s: authctxt not valid", __func__);
1427         blob = buffer_get_string(m, &blen);
1428         if (!monitor_allowed_key(blob, blen))
1429                 fatal("%s: bad key, not previously allowed", __func__);
1430         if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY)
1431                 fatal("%s: key type mismatch", __func__);
1432         if ((key = key_from_blob(blob, blen)) == NULL)
1433                 fatal("%s: received bad key", __func__);
1434
1435         if (ssh1_challenge)
1436                 BN_clear_free(ssh1_challenge);
1437         ssh1_challenge = auth_rsa_generate_challenge(key);
1438
1439         buffer_clear(m);
1440         buffer_put_bignum2(m, ssh1_challenge);
1441
1442         debug3("%s sending reply", __func__);
1443         mm_request_send(sock, MONITOR_ANS_RSACHALLENGE, m);
1444
1445         monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 1);
1446
1447         xfree(blob);
1448         key_free(key);
1449         return (0);
1450 }
1451
1452 int
1453 mm_answer_rsa_response(int sock, Buffer *m)
1454 {
1455         Key *key = NULL;
1456         u_char *blob, *response;
1457         u_int blen, len;
1458         int success;
1459
1460         debug3("%s entering", __func__);
1461
1462         if (!authctxt->valid)
1463                 fatal("%s: authctxt not valid", __func__);
1464         if (ssh1_challenge == NULL)
1465                 fatal("%s: no ssh1_challenge", __func__);
1466
1467         blob = buffer_get_string(m, &blen);
1468         if (!monitor_allowed_key(blob, blen))
1469                 fatal("%s: bad key, not previously allowed", __func__);
1470         if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY)
1471                 fatal("%s: key type mismatch: %d", __func__, key_blobtype);
1472         if ((key = key_from_blob(blob, blen)) == NULL)
1473                 fatal("%s: received bad key", __func__);
1474         response = buffer_get_string(m, &len);
1475         if (len != 16)
1476                 fatal("%s: received bad response to challenge", __func__);
1477         success = auth_rsa_verify_response(key, ssh1_challenge, response);
1478
1479         xfree(blob);
1480         key_free(key);
1481         xfree(response);
1482
1483         auth_method = key_blobtype == MM_RSAUSERKEY ? "rsa" : "rhosts-rsa";
1484
1485         /* reset state */
1486         BN_clear_free(ssh1_challenge);
1487         ssh1_challenge = NULL;
1488         monitor_reset_key_state();
1489
1490         buffer_clear(m);
1491         buffer_put_int(m, success);
1492         mm_request_send(sock, MONITOR_ANS_RSARESPONSE, m);
1493
1494         return (success);
1495 }
1496
1497 int
1498 mm_answer_term(int sock, Buffer *req)
1499 {
1500         extern struct monitor *pmonitor;
1501         int res, status;
1502
1503         debug3("%s: tearing down sessions", __func__);
1504
1505         /* The child is terminating */
1506         session_destroy_all(&mm_session_close);
1507
1508         while (waitpid(pmonitor->m_pid, &status, 0) == -1)
1509                 if (errno != EINTR)
1510                         exit(1);
1511
1512         res = WIFEXITED(status) ? WEXITSTATUS(status) : 1;
1513
1514         /* Terminate process */
1515         exit(res);
1516 }
1517
1518 #ifdef SSH_AUDIT_EVENTS
1519 /* Report that an audit event occurred */
1520 int
1521 mm_answer_audit_event(int socket, Buffer *m)
1522 {
1523         ssh_audit_event_t event;
1524
1525         debug3("%s entering", __func__);
1526
1527         event = buffer_get_int(m);
1528         switch(event) {
1529         case SSH_AUTH_FAIL_PUBKEY:
1530         case SSH_AUTH_FAIL_HOSTBASED:
1531         case SSH_AUTH_FAIL_GSSAPI:
1532         case SSH_LOGIN_EXCEED_MAXTRIES:
1533         case SSH_LOGIN_ROOT_DENIED:
1534         case SSH_CONNECTION_CLOSE:
1535         case SSH_INVALID_USER:
1536                 audit_event(event);
1537                 break;
1538         default:
1539                 fatal("Audit event type %d not permitted", event);
1540         }
1541
1542         return (0);
1543 }
1544
1545 int
1546 mm_answer_audit_command(int socket, Buffer *m)
1547 {
1548         u_int len;
1549         char *cmd;
1550
1551         debug3("%s entering", __func__);
1552         cmd = buffer_get_string(m, &len);
1553         /* sanity check command, if so how? */
1554         audit_run_command(cmd);
1555         xfree(cmd);
1556         return (0);
1557 }
1558 #endif /* SSH_AUDIT_EVENTS */
1559
1560 void
1561 monitor_apply_keystate(struct monitor *pmonitor)
1562 {
1563         if (compat20) {
1564                 set_newkeys(MODE_IN);
1565                 set_newkeys(MODE_OUT);
1566         } else {
1567                 packet_set_protocol_flags(child_state.ssh1protoflags);
1568                 packet_set_encryption_key(child_state.ssh1key,
1569                     child_state.ssh1keylen, child_state.ssh1cipher);
1570                 xfree(child_state.ssh1key);
1571         }
1572
1573         /* for rc4 and other stateful ciphers */
1574         packet_set_keycontext(MODE_OUT, child_state.keyout);
1575         xfree(child_state.keyout);
1576         packet_set_keycontext(MODE_IN, child_state.keyin);
1577         xfree(child_state.keyin);
1578
1579         if (!compat20) {
1580                 packet_set_iv(MODE_OUT, child_state.ivout);
1581                 xfree(child_state.ivout);
1582                 packet_set_iv(MODE_IN, child_state.ivin);
1583                 xfree(child_state.ivin);
1584         }
1585
1586         memcpy(&incoming_stream, &child_state.incoming,
1587             sizeof(incoming_stream));
1588         memcpy(&outgoing_stream, &child_state.outgoing,
1589             sizeof(outgoing_stream));
1590
1591         /* Update with new address */
1592         if (options.compression)
1593                 mm_init_compression(pmonitor->m_zlib);
1594
1595         /* Network I/O buffers */
1596         /* XXX inefficient for large buffers, need: buffer_init_from_string */
1597         buffer_clear(&input);
1598         buffer_append(&input, child_state.input, child_state.ilen);
1599         memset(child_state.input, 0, child_state.ilen);
1600         xfree(child_state.input);
1601
1602         buffer_clear(&output);
1603         buffer_append(&output, child_state.output, child_state.olen);
1604         memset(child_state.output, 0, child_state.olen);
1605         xfree(child_state.output);
1606 }
1607
1608 static Kex *
1609 mm_get_kex(Buffer *m)
1610 {
1611         Kex *kex;
1612         void *blob;
1613         u_int bloblen;
1614
1615         kex = xmalloc(sizeof(*kex));
1616         memset(kex, 0, sizeof(*kex));
1617         kex->session_id = buffer_get_string(m, &kex->session_id_len);
1618         if ((session_id2 == NULL) ||
1619             (kex->session_id_len != session_id2_len) ||
1620             (memcmp(kex->session_id, session_id2, session_id2_len) != 0))
1621                 fatal("mm_get_get: internal error: bad session id");
1622         kex->we_need = buffer_get_int(m);
1623         kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
1624         kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
1625         kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1626         kex->server = 1;
1627         kex->hostkey_type = buffer_get_int(m);
1628         kex->kex_type = buffer_get_int(m);
1629         blob = buffer_get_string(m, &bloblen);
1630         buffer_init(&kex->my);
1631         buffer_append(&kex->my, blob, bloblen);
1632         xfree(blob);
1633         blob = buffer_get_string(m, &bloblen);
1634         buffer_init(&kex->peer);
1635         buffer_append(&kex->peer, blob, bloblen);
1636         xfree(blob);
1637         kex->done = 1;
1638         kex->flags = buffer_get_int(m);
1639         kex->client_version_string = buffer_get_string(m, NULL);
1640         kex->server_version_string = buffer_get_string(m, NULL);
1641         kex->load_host_key=&get_hostkey_by_type;
1642         kex->host_key_index=&get_hostkey_index;
1643
1644         return (kex);
1645 }
1646
1647 /* This function requries careful sanity checking */
1648
1649 void
1650 mm_get_keystate(struct monitor *pmonitor)
1651 {
1652         Buffer m;
1653         u_char *blob, *p;
1654         u_int bloblen, plen;
1655         u_int32_t seqnr, packets;
1656         u_int64_t blocks;
1657
1658         debug3("%s: Waiting for new keys", __func__);
1659
1660         buffer_init(&m);
1661         mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, &m);
1662         if (!compat20) {
1663                 child_state.ssh1protoflags = buffer_get_int(&m);
1664                 child_state.ssh1cipher = buffer_get_int(&m);
1665                 child_state.ssh1key = buffer_get_string(&m,
1666                     &child_state.ssh1keylen);
1667                 child_state.ivout = buffer_get_string(&m,
1668                     &child_state.ivoutlen);
1669                 child_state.ivin = buffer_get_string(&m, &child_state.ivinlen);
1670                 goto skip;
1671         } else {
1672                 /* Get the Kex for rekeying */
1673                 *pmonitor->m_pkex = mm_get_kex(&m);
1674         }
1675
1676         blob = buffer_get_string(&m, &bloblen);
1677         current_keys[MODE_OUT] = mm_newkeys_from_blob(blob, bloblen);
1678         xfree(blob);
1679
1680         debug3("%s: Waiting for second key", __func__);
1681         blob = buffer_get_string(&m, &bloblen);
1682         current_keys[MODE_IN] = mm_newkeys_from_blob(blob, bloblen);
1683         xfree(blob);
1684
1685         /* Now get sequence numbers for the packets */
1686         seqnr = buffer_get_int(&m);
1687         blocks = buffer_get_int64(&m);
1688         packets = buffer_get_int(&m);
1689         packet_set_state(MODE_OUT, seqnr, blocks, packets);
1690         seqnr = buffer_get_int(&m);
1691         blocks = buffer_get_int64(&m);
1692         packets = buffer_get_int(&m);
1693         packet_set_state(MODE_IN, seqnr, blocks, packets);
1694
1695  skip:
1696         /* Get the key context */
1697         child_state.keyout = buffer_get_string(&m, &child_state.keyoutlen);
1698         child_state.keyin  = buffer_get_string(&m, &child_state.keyinlen);
1699
1700         debug3("%s: Getting compression state", __func__);
1701         /* Get compression state */
1702         p = buffer_get_string(&m, &plen);
1703         if (plen != sizeof(child_state.outgoing))
1704                 fatal("%s: bad request size", __func__);
1705         memcpy(&child_state.outgoing, p, sizeof(child_state.outgoing));
1706         xfree(p);
1707
1708         p = buffer_get_string(&m, &plen);
1709         if (plen != sizeof(child_state.incoming))
1710                 fatal("%s: bad request size", __func__);
1711         memcpy(&child_state.incoming, p, sizeof(child_state.incoming));
1712         xfree(p);
1713
1714         /* Network I/O buffers */
1715         debug3("%s: Getting Network I/O buffers", __func__);
1716         child_state.input = buffer_get_string(&m, &child_state.ilen);
1717         child_state.output = buffer_get_string(&m, &child_state.olen);
1718
1719         buffer_free(&m);
1720 }
1721
1722
1723 /* Allocation functions for zlib */
1724 void *
1725 mm_zalloc(struct mm_master *mm, u_int ncount, u_int size)
1726 {
1727         size_t len = (size_t) size * ncount;
1728         void *address;
1729
1730         if (len == 0 || ncount > SIZE_T_MAX / size)
1731                 fatal("%s: mm_zalloc(%u, %u)", __func__, ncount, size);
1732
1733         address = mm_malloc(mm, len);
1734
1735         return (address);
1736 }
1737
1738 void
1739 mm_zfree(struct mm_master *mm, void *address)
1740 {
1741         mm_free(mm, address);
1742 }
1743
1744 void
1745 mm_init_compression(struct mm_master *mm)
1746 {
1747         outgoing_stream.zalloc = (alloc_func)mm_zalloc;
1748         outgoing_stream.zfree = (free_func)mm_zfree;
1749         outgoing_stream.opaque = mm;
1750
1751         incoming_stream.zalloc = (alloc_func)mm_zalloc;
1752         incoming_stream.zfree = (free_func)mm_zfree;
1753         incoming_stream.opaque = mm;
1754 }
1755
1756 /* XXX */
1757
1758 #define FD_CLOSEONEXEC(x) do { \
1759         if (fcntl(x, F_SETFD, 1) == -1) \
1760                 fatal("fcntl(%d, F_SETFD)", x); \
1761 } while (0)
1762
1763 static void
1764 monitor_socketpair(int *pair)
1765 {
1766 #ifdef HAVE_SOCKETPAIR
1767         if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1)
1768                 fatal("%s: socketpair", __func__);
1769 #else
1770         fatal("%s: UsePrivilegeSeparation=yes not supported",
1771             __func__);
1772 #endif
1773         FD_CLOSEONEXEC(pair[0]);
1774         FD_CLOSEONEXEC(pair[1]);
1775 }
1776
1777 #define MM_MEMSIZE      65536
1778
1779 struct monitor *
1780 monitor_init(void)
1781 {
1782         struct monitor *mon;
1783         int pair[2];
1784
1785         mon = xmalloc(sizeof(*mon));
1786
1787         mon->m_pid = 0;
1788         monitor_socketpair(pair);
1789
1790         mon->m_recvfd = pair[0];
1791         mon->m_sendfd = pair[1];
1792
1793         /* Used to share zlib space across processes */
1794         if (options.compression) {
1795                 mon->m_zback = mm_create(NULL, MM_MEMSIZE);
1796                 mon->m_zlib = mm_create(mon->m_zback, 20 * MM_MEMSIZE);
1797
1798                 /* Compression needs to share state across borders */
1799                 mm_init_compression(mon->m_zlib);
1800         }
1801
1802         return mon;
1803 }
1804
1805 void
1806 monitor_reinit(struct monitor *mon)
1807 {
1808         int pair[2];
1809
1810         monitor_socketpair(pair);
1811
1812         mon->m_recvfd = pair[0];
1813         mon->m_sendfd = pair[1];
1814 }
1815
1816 #ifdef GSSAPI
1817 int
1818 mm_answer_gss_setup_ctx(int sock, Buffer *m)
1819 {
1820         gss_OID_desc goid;
1821         OM_uint32 major;
1822         u_int len;
1823
1824         goid.elements = buffer_get_string(m, &len);
1825         goid.length = len;
1826
1827         major = ssh_gssapi_server_ctx(&gsscontext, &goid);
1828
1829         xfree(goid.elements);
1830
1831         buffer_clear(m);
1832         buffer_put_int(m, major);
1833
1834         mm_request_send(sock,MONITOR_ANS_GSSSETUP, m);
1835
1836         /* Now we have a context, enable the step */
1837         monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1);
1838
1839         return (0);
1840 }
1841
1842 int
1843 mm_answer_gss_accept_ctx(int sock, Buffer *m)
1844 {
1845         gss_buffer_desc in;
1846         gss_buffer_desc out = GSS_C_EMPTY_BUFFER;
1847         OM_uint32 major,minor;
1848         OM_uint32 flags = 0; /* GSI needs this */
1849         u_int len;
1850
1851         in.value = buffer_get_string(m, &len);
1852         in.length = len;
1853         major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags);
1854         xfree(in.value);
1855
1856         buffer_clear(m);
1857         buffer_put_int(m, major);
1858         buffer_put_string(m, out.value, out.length);
1859         buffer_put_int(m, flags);
1860         mm_request_send(sock, MONITOR_ANS_GSSSTEP, m);
1861
1862         gss_release_buffer(&minor, &out);
1863
1864         if (major==GSS_S_COMPLETE) {
1865                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0);
1866                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
1867                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1);
1868         }
1869         return (0);
1870 }
1871
1872 int
1873 mm_answer_gss_checkmic(int sock, Buffer *m)
1874 {
1875         gss_buffer_desc gssbuf, mic;
1876         OM_uint32 ret;
1877         u_int len;
1878
1879         gssbuf.value = buffer_get_string(m, &len);
1880         gssbuf.length = len;
1881         mic.value = buffer_get_string(m, &len);
1882         mic.length = len;
1883
1884         ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic);
1885
1886         xfree(gssbuf.value);
1887         xfree(mic.value);
1888
1889         buffer_clear(m);
1890         buffer_put_int(m, ret);
1891
1892         mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m);
1893
1894         if (!GSS_ERROR(ret))
1895                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
1896
1897         return (0);
1898 }
1899
1900 int
1901 mm_answer_gss_userok(int sock, Buffer *m)
1902 {
1903         int authenticated;
1904
1905         authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user);
1906
1907         buffer_clear(m);
1908         buffer_put_int(m, authenticated);
1909
1910         debug3("%s: sending result %d", __func__, authenticated);
1911         mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m);
1912
1913         auth_method="gssapi-with-mic";
1914
1915         /* Monitor loop will terminate if authenticated */
1916         return (authenticated);
1917 }
1918 #endif /* GSSAPI */